FOOD, FAT, FATIGUE AND INSULIN
Make your calories work for you instead of against you.
By John R. Lee, M.D. and Virginia Hopkins
Fat makes you fat, right? And calories are calories, regardless of where they come from. If only it were that simple. In truth, your body does very different things with fats, sugars, other carbohydrates and proteins. It also responds differently depending on how you combine food groups. For example, a combination of fat, carbohydrate and sugar (think pastries and cookies) can create blood sugar havoc, while fat, complex carbohydrates and protein (think meat and whole grain rice) can create blood sugar stability. Stable blood sugar is one of the foundations of maintaining a healthy weight.
However, everything I’m about to say comes with one big caveat: moderation. If you eat enormous amounts of food you’re going to become enormous regardless of what diet you’re on. If you eat mostly white, doughy foods, your body is going to be white and doughy. None of the women I described above were over-eating; they were eating in a way that encouraged their bodies to put on weight instead of losing or maintaining it.
As most of you know, three basic kinds of foods are converted into fuel: proteins, fats and carbohydrates. Proteins, such as dairy products, meats, fish and eggs, are broken down into amino acids. Fats such as butter, cream, bacon and oils are broken down into fatty acids. Carbohydrates— whether from cakes, candy, fruits, potatoes, grains or starchy vegetables—are broken down into simple sugars. Mis-use and abuse of sugars is where most Americans get their fat and their fatigue.
What Sugar Does in Your Body
Sugar enters the bloodstream in a form called glucose, the main source of fuel for the body, and especially the brain. The cells that ultimately use the glucose for fuel do not care whether it originally came from Ben and Jerry’s ice cream or the carbohydrates in broccoli. What does dramatically affect your body is how fast the glucose enters the bloodstream. Ben and Jerry’s will cause a quick, large surge in glucose, while broccoli will cause only the slightest rise over time. Excess glucose is toxic to the kidneys and other organs, and this is where insulin comes in. In response to rising glucose, the pancreas secretes the hormone insulin into the bloodstream. Insulin’s job is to transport glucose out of the bloodstream and into your cells, which is why a big surge of glucose causes a big release of insulin. However, too much insulin is also toxic, so your body works hard to maintain balance. Researchers estimate that there are as many as 20,000 insulin receptors or more per cell.
As your glucose level gradually falls after a meal or snack, the amount of insulin in the blood also falls. At any given time the blood can carry about an hour’s supply of glucose. Any glucose that is not needed for immediate energy is converted into glycogen and stored in the liver and muscles. When it is required for energy, the liver turns the glycogen back into glucose. The body can store only enough glycogen to last for several hours of moderate activity. Finally, when its glycogen is used up, the body turns to stored fat for fuel. When glucose levels rise, your body stops using stored fat. Thus, you can understand why my friend who drinks Cokes all day long isn’t losing weight—her body has no need to burn its fat because she’s constantly feeding it instant glucose!
Inside the insulin receptor is an enzyme called tyrosine kinase (TK). Once activated by insulin this enzyme triggers a cascade of events that open channels through which glucose can enter the cells to be stored or used for energy. When cells become insulin resistant, the channels do not open and the glucose fails to gain entry into the cells. Insulin resistance causes glucose to build up in the bloodstream, which in turn signals the pancreas to make more insulin. The end result is higher-than-normal levels of both insulin and glucose in the bloodstream, which promotes the formation of fat and causes abnormal cholesterol, high triglycerides, high blood pressure and eventually, clogged arteries. In fact, when you’re insulin resistant, the only cells in the body that benefit from excess sugar are cancer cells, which happily use it for energy and growth.
Researchers in the Framingham Study estimate that as much as 60 percent of heart disease in women is caused by insulin resistance. The constellation of symptoms caused by insulin resistance has come to be known as Syndrome X, a term coined by Gerald Reaven, M.D., a Stanford University researcher.
Over time, insulin resistance will cause muscle cells to weaken due to lack of fuel, and thus begins a vicious cycle of less exercise, more weight gain, and more insulin resistance. As fat increases and muscle decreases, the body loses more and more of its ability to burn fuel efficiently and metabolism slows to a crawl.
Insulin resistance is often the precursor to type 2 diabetes. Clearly, eating sugars and simple carbohydrates when you’re insulin resistant will only make it worse.
We don’t know the exact mechanisms that cause insulin resistance, but we do know that insulin resistance, abdominal obesity, and stress tend to go hand-in-hand. The high cortisol levels caused by stress tend to cause abdominal obesity, which in turn is one of the hallmarks of insulin resistance. So if you tend to head for the ice cream, pastries and cookies when you’re stressed, it may be time to look for a different coping mechanism.
And by the way, you can be slim and still be insulin resistant, with all of the fatigue and other damage still occurring in the body. My guess is that chronic stress combined with genetic predisposition and a sugar-laden diet are the common threads of insulin resistance.
Slowing the Glucose Train
Clearly, big surges of glucose are the foundation of fat and fatigue. So how do we slow the glucose train? The most obvious answer is to not eat sugar and refined carbohydrates. But getting enough protein and eating some fat can also help, and that’s why diets which shun protein or fat can cause weight gain and fatigue.
Whole grains, fiber, protein and fat can all help slow things down. Complex carbohydrates such as those found in whole grains, fresh vegetables, nuts, seeds and beans, tend to break down slowly in the gut and cause a very gradual rise in blood sugar. Complex carbohydrates tend to be higher in fiber, which also slows down the digestive process.
The body breaks proteins down into amino acids, some of which are stored in the liver for the manufacture of glucagon, which is what allows the release of glycogen, which you’ll remember is the body’s backup system when glucose levels start to fall after a meal. No protein means no glycogen, which means no backup glucose, which means intense sugar/carbohydrate cravings as the body signals for more glucose—fast!
This is why the vegetarian who eats a bagel for breakfast (a simple carbohydrate which breaks down quickly into glucose); a banana (fruit sugar); a salad with bread etc. (more simple carbohydrates); a protein bar (they’re all loaded with sugar); or trail mix (raisins are very sweet); and more carbohydrates with dinner, but very little protein throughout the day, is gaining weight and feeling tired. She’d be better off having a piece of whole grain toast with butter and an egg for breakfast; tofu with her salad for lunch, and fish for dinner, for example.
When I talk about fats as good foods, I’m not talking about the trans fatty acids (hydrogenated oils) found in almost all processed foods—please avoid those.
Fat slows the glucose train for a number of reasons. As fat hits the taste buds, it sends signals to the rest of the gastrointestinal system that rich fuel and calories are coming, and that creates “I’m satisfied” or satiety signals. Fats—and especially saturated fats—are easy to digest, are burned for fuel quickly and efficiently, and tend to speed up metabolism in general while slowing the digestion of sugars.
As long as you’re moderate in your fat consumption, your body is very good at ridding itself of excess fats, including cholesterol.
Find What Works Best for You
Always keep in mind that we’re each unique in our genetic makeup and biochemistry, and what works well for one person may not work for another. One person may thrive on meat and vegetables, while another may thrive on fish and rice, and yet another may need a minimum of protein and more carbohydrates. If you keep the above principles in mind, you can eat in a way that’s very satisfying and yet doesn’t keep increasing your weight. If you’re having trouble finding the right “food tune” for your body, I would recommend that you get Dr. Harold Kristal’s new book, The Nutrition Solution: A Guide to Your Metabolic Type, which is referred to in the article by Dr. Kristal in the November 2002 issue of this newsletter.
Good luck, and let me know how it goes!
Prescription drugs that can cause high blood sugar
Here are some prescription drugs that can cause hyperglycemia, or high blood sugar.
- Calcium channel blockers for heart arrhythmias [nifedipine (Procardia), nicardipine (Cardene), diltiazem (Cardizem), verapamil]
- Antihypertensives that lower blood pressure (clonidine, diazoixde, diuretics)
- Corticosteroids (Prednisone)
- Epinephrine (bronchodilators, decongestants)
- Heparin to prevent blood clotting
- Thyroid drugs for low thyroid (Levoxine, Synthroid)
- Pentamidine for the treatment of pneumonia
- Phenytoin for the treatment of seizures (Dilantin)
- Antituberculosis drugs [rifampin (Rifadin, Rimactane), isoniazid (Laniazid, Nydrazid)